Removing Rust on Knives

Customers often come to us and mention that their knives have rusted and become unusable. If a knife suddenly turns completely black due to rust, it may seem beyond repair at first. This is a normal reaction, the knife looks completely different after all.

Using a rusted knife for cutting ingredients can be very unappealing, and some would imagine unhealthy too. However, in many cases, initial rust is only on the surface and can be cleaned by polishing. It's crucial to address rust promptly, as leaving it untreated may lead to deeper penetration, making repair impossible.

Most importantly, don't give up on your knife if you see rust - as it's likely not too late to save it!

The environment in which knives are used is generally quite harsh for metals.

Cooking requires constant exposure to water, and cutting ingredients often involves items with high salt content or acidity, making it challenging to prevent rust on knives. Rust is a natural reaction to oxygen and water oxidising on iron, converting it it back into iron oxide - it's natural state.

In this sense, the occurrence of rust on knives might be inevitable. However, once rust appears, it won't disappear on its own, so it's crucial to promptly remove rust when you first see it without delay.

Rust in the initial stage is actually quite easy to remove. Since it's only on the surface, a light polishing is usually enough. Again, it's important to get on this quickly as the worse the rust gets, the harder it is to remove and the more penetrative it gets into the blade, meaning you need to remove more of it to save it.

When polishing, it's important to use an abrasive agent to effectively remove rust. If rust remains or isn't properly treated afterwards, there is a risk of it spreading again.

There's a few ways you can remove rust, which we've listed below:

Use a rust-removing rubber/eraser - Miracle Clean

One of the methods we apply in store is using a specialized rust eraser called "Miracle Clean." You may see this as ミラクルクリーン or mirakurukuriin in Japanese. We recommend this product very strongly!

Miracle Clean is a eraser-like tool for knives that contains abrasive agents. By using Miracle Clean to polish the rusted areas, even large amounts of surface rust can be effectively removed. Generally, this product isn't too expensive either - we sell it in store in various sizes. Some people will purchase blade oil and Miracle Clean together when they buy knives.

The key to successfully removing rust is to follow the grind marks or lines on the knife's blade. Polish along these marks using the Miracle Clean and the rust should come off easily, leaving a beautiful knife in its place.

Use water-resistant paper

At places like home improvement centers or tool and hardware stores, you'll find various kinds of abrasive paper. Some of them are waterproof or water-resistant and these can be used for rust removal. This comes in various coarseness or grit sizes, much like whetstones. The severity of the rust determines what coarseness you should buy - larger spots of rust should use a coarser grit, and finer grits work for smaller areas.

Types of abrasive papers can include sandpaper, waterproof paper and air-sanding paper. In the case of knives, it's recommended to choose waterproof paper. This is because knives themselves are best sharpened with water, so this makes the paper also practical for future use.

Polish using cleanser

If you want to remove rust using items you have at home, you can use a cleanser to polish the knife. Cleansers typically contain abrasives, allowing you to remove rust.

Apply the cleanser to the knife and use the back of a sponge to polish the blade, and the rust should come off.If the rust is more severe, consider using a metal scrubber or steel wool instead of a sponge for better results.

If you're running into trouble, consider one of the other, more specialised methods above. Alternatively, feel free to contact us if this is tricky, isn't working or if your knife is a special heirloom piece! We can always help you with rust removal on your knives - provided you reach out to us before the rust penetrates too deeply. We're specialists in sharpening and rust removal is a part of that process, so we can bring many knives back to a wonderful state.

Don't give up on your knives! Prevent rust first, but if you aren't able to they can still be saved!